EVALUATION OF THE POTENTIAL CARDIOTOXICITY OF THE ANTIHISTAMINES TERFENADINE, ASTEMIZOLE, LORATADINE, AND CETIRIZINE IN ATOPIC CHILDREN

Background: Adverse cardiac effects have been related to the use of H- 1-receptor antagonists terfenadine and astemizole. Objective: We have investigated the cardiac effects of the H-1-receptor antagonists terfe nadine, astemizole, loratadine and cetirizine, used in recommended dos es, concomitantly or not with the antibiotic erythromycin. Methods: A group of 80 children aged 5 to 12 years was studied. All children had been diagnosed with perennial allergic rhinitis based on symptoms, cli nical signs and a positive immediate skin test to Dermatophagoides pte ronyssinus. The children had no personal history of cardiac disease or hepatic dysfunction, and they had a normal electrocardiogram (ECG) at the beginning of the study. Forty children had allergic rhinitis and sinusitis, and were assigned to subgroups of ten children who received terfenadine, astemizole, loratadine, or cetirizine, concomitantly wit h erythromycin, for 14 days. Erythromycin was started to treat presume d bacterial infection in children with complete radiologic opacificati on of the maxillary sinus(es). The remaining 40 children had no sinusi tis, and were assigned to subgroups of 10 children who received terfen adine, astemizole, loratadine, or cetirizine for 14 days. Results: No significant changes in the QT interval and QTc (QT corrected by Bazzet t's equation) were observed among children who received astemizole, lo ratadine or cetirizine, with or without erythromycin. Children who hav e received terfenadine and erythromycin showed significantly prolonged QT interval (mean pretreatment and posttreatment values 0.32s and 0.3 4s, respectively). Analysis of the QTc interval, however, showed no si gnificant differences in the group treated with terfenadine and erythr omycin (mean values 0.39s and 0.39s, respectively). Conclusions: Our r esults show that H-1-receptor antagonists terfenadine, astemizole, lor atadine and cetirizine, administered with or without erythromycin, to atopic children in recommended doses, do not induce adverse cardiac ef fects. Although the association between terfenadine and erythromycin h as caused a statistically significant increase in QT interval measurem ents, the magnitude of these changes was below levels considered cardi otoxic or clinically relevant.